Am 29.08.2012 10:41, schrieb mathieu_r:
> The preivous image was too big. Here it is.

Hey, that looks great!


>>> -> "completely radiosity-lit"
>>> I have put some radiosity on my scene, also some light sources. How to make it
>>> **completely** radiosity-lit

To light a scene using only radiosity, you'd replace all your light 
sources with

a) objects which emit light by themselves (using the "emission" keyword 
in the finish; make sure to use big objects, or drastically increase the 
radiosity "count" parameter), and/or

b) a sky_sphere or bright background (giving you light from all directions)

You may need to increase the recursion depth by 1, as compared to a 
normally-lit scene.


>>> -> "a bright blue"
>>> How to influence on light brightness?

Sorry, I actually meant "light blue".

But since you're asking: The easiest way to change a light source's 
brightness is via its color; for instance, <0.5, 0.0, 0.0> will give you 
a dim red, while <10, 0, 0> will give you a very bright red of the same 
hue and saturation.

You can also multiply a given color by a constant, such as <1,0,0>*0.5 
or <1,0,0>*10; IIRC this should also work with color constants, e.g. Red*10.

>>> We can influence the light brightness by making it far from the object?

That depends. By default, the illumination from a light source is 
independent of its distance (which of course is unrealistic). However, 
with the "fade_distance" and "fade_power" keywords you can get more 
realistic behaviour.

fade_power should be set to 2 for this purpose. fade_distance is best 
set to the presumed radius of the light source (half the area light's size).

Note that this will typically make your illumination a /lot/ darker; 
you'll have to compensate for this by cranking up the light source's 
nominal brightness as described above. For instance, if fade_power is 
set to 2, fade_distance to 10, and the light is at a distance of 1000, 
then you'll need to increase the brightness by a factor of (1000/10)^2 
to get the same brightness as without the fade_* keywords.

>>> -> "very diffuse lighting"
>>> How to make lighting very diffuse?

Use area lights with a big size (alternatively, a radiosity-lit scene 
with large emissive objects and/or a sky sphere), and set hightlights to 
zero (phong 0 specular 0).

>>> -> "I guess that a bit of fog might also be needed."
>>> Does the fog paramter seem correct to you?

I personally don't think the scene needs any fog.


As another suggestion, I'd recommend some slight focal blur (see the 
"aperture" camera keyword).

Post a reply to this message